JP3169272B2 - Apparatus for calculating remaining battery life - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention calculates the remaining use time of a battery by accurately calculating the dischargeable time that changes with the discharge of the battery, that is, the remaining use time in consideration of the magnitude of the discharge current of the battery. Related to the device.

[0002]

2. Description of the Related Art In an electronic / electric device in which a rechargeable battery (rechargeable battery) is incorporated as a power source, for example, a shaving apparatus, a time required until charging is required, that is, a capacity remaining in the battery. The dischargeable time (remaining use time) is one of the concerns for the user. By grasping the remaining use time, for example, it is possible to avoid a situation in which the battery capacity is lost during use and shaving is interrupted.

[0003] As a conventional device for indirectly knowing the remaining usage time, a configuration for displaying the remaining capacity of a battery is known. For example, Japanese Patent Application Laid-Open No. 622-272827 discloses an apparatus that calculates the charge / discharge amount of a battery by measuring a charge / discharge time, and displays the calculation result as a bar graph. Also, West German Patent Application Publication No. 231356
No. 6 describes a device that measures a charge current / discharge current of a battery and obtains a charge / discharge amount of the battery based on the measurement result.

[0004] Even when the remaining capacity of the battery is displayed using these techniques, it is very difficult to predict how long the battery can be used thereafter, that is, the remaining usage time, from the remaining capacity. Therefore, it is conceivable to obtain the remaining use time by dividing the remaining capacity by a predetermined coefficient (for example, an average discharge current).

[0005]

For example, if the nominal capacity is 60
For a 0 mAh battery, the discharge capacity allowed when charging is completed
Assume 500mAh (compensation capacity). When the average discharge current (coefficient) at the time of shaving is 700 mA, the remaining use time at the time of completion of charging is about 42 minutes. That is, when the shaving apparatus is used for 42 minutes (discharged with a current of 700 mAh) after charging is completed, the display of the remaining use time decreases from 42 minutes to 0 minutes.

However, in a shaving apparatus,
The load fluctuates according to the usage mode. For example, if the shaving apparatus is provided with a trimmer function, using this trimmer function makes the motor load heavier than during shaving, and the driving current of the motor, that is, the discharge current of the battery, is about 1.5 times that during shaving. Become. In addition, when the motor is driven with the blade removed to clean the shaving apparatus, the load on the motor is reduced as compared with the time of shaving, and the discharge current of the battery is reduced to about half that during shaving.

If the discharge current of the battery is greater than 700 mA, the actual use time of the shaving apparatus is less than 42 minutes, and if it is less than 700 mAh,
It will be longer than 42 minutes. This means that the process in which the remaining usage time shifts from 42 minutes to 0 minutes is not proportional to the absolute time 42 minutes. If the load is heavy, the remaining usage time is reduced from 42 minutes to 0 minutes in a time shorter than the absolute time 42 minutes. Minutes,
When the load is light, the remaining usage time shifts from 42 minutes to 0 minutes in a time longer than the absolute time 42 minutes. Specifically, the discharge current greatly differs between a usage mode in which the trimmer function is frequently used and a usage mode in which the trimmer function is not used. That is, the total time differs. Conventionally, such fluctuations and magnitudes of the discharge current are not considered, and in each case, the remaining use time is calculated based on the average discharge current assumed uniformly. There has been a problem that the dischargeable times do not match, that is, the discharge (use) can be actually performed only for a time shorter than the value indicated by the remaining use time.

[0008]

SUMMARY OF THE INVENTION The present invention accurately calculates the total time required for discharging a capacity after the completion of charging in consideration of fluctuations in the discharge current of a battery, and as a result, the remaining usage time that changes with discharging. And a device for calculating the remaining use time of the battery which can avoid the situation where the discharge (use) can be actually performed only for a shorter time than the value indicated by the remaining use time.

The present invention is characterized in that a battery having a compensation capacity set as a capacity at the time of completion of charging, a time measuring means for measuring a use time after the charging of the battery is stopped, and a discharge capacity at the time of use of the battery. Each time the integrating means for integrating and the integrating means complete the integration of the reference capacity which is a part of the compensation capacity,
Storage means for storing a plurality of the use times measured by the clock means, average time calculation means for calculating an average value of the plurality of use times stored in the storage means, and matching the reference capacity with the compensation capacity Total time calculating means for calculating a total time for the compensation capacity by multiplying a constant which is a magnification to be multiplied by the average value, and multiplying the total time by a proportional value indicating a ratio between the compensation capacity and the discharge capacity. And a remaining use time calculating means for calculating the remaining use time. A further feature of the present invention is that a resistor inserted in series with the battery and an absolute value of a voltage generated in the resistor are detected based on a current flowing through the resistor, and a pulse having a frequency corresponding to the voltage is detected. And a converter for outputting, and the integration of the discharge capacity by the integrating means is realized by counting the pulses. A further feature of the present invention is that a time display unit for displaying the remaining use time is provided. A further feature of the present invention is that the integrating means integrates a charging capacity when charging the battery.

[0010] The timer measures the usage time after the charging of the battery is stopped. At the same time, the integrating means integrates the discharge capacity of the battery. Then, the integrating means calculates a constant rate based on the compensation capacity of the battery, for example, a compensation capacity of 50.
Assuming that 0 mAh is 100%, the storage means stores the usage time counted by the time counting means every time the reference capacity 50 mAh corresponding to 10% of the compensation capacity is counted. On the other hand, at a predetermined cycle set in advance, the average time calculating means calculates an average value of the plurality of use times stored in the storage means, and the total time calculating means multiplies the average value by a constant. Calculate the total time that is the value. The total time reflects the latest use time required to discharge the reference capacity, and thus has a content according to the magnitude of the actual discharge current. Further, the remaining use time calculating means calculates a ratio of the count result of the integrating means to the compensation capacity, and calculates a remaining use time which is a product of the ratio and the total time. Since the total time is based on the actual discharge current, the remaining use time also reflects the actual discharge current. Therefore, the value indicating the remaining use time can always indicate the content corresponding to the absolute time during which the battery can be actually used.

[0011]

FIG. 1 shows a block diagram of the apparatus of the present invention.
In the apparatus shown in the figure, the negative output terminal of a rechargeable battery 1 such as a Ni-Cd battery is grounded, and the positive output terminal is one end of a motor 2 driving a shaving blade and one end of a shaving switch 3. It is connected to the. The other end of the motor 2 is connected to the collector of the transistor Tr. The base of the transistor Tr is connected to the shaving switch 3 via the resistor R.
And the emitter is grounded via a motor current detection resistor Rs. Further, the positive output terminal of the battery 1 is connected to the positive output of the charging circuit 5 via the charging switch 4, and the negative output of the charging circuit 5 is connected to the emitter of the transistor Tr. For example, an AC power supply is connected to the input side of the charging circuit 5.

The input side of the absolute value circuit 6 is connected to the emitter of the transistor Tr. The absolute value circuit 6 determines whether the absolute value of the voltage generated in the resistor Rs, that is, the direction of the current flowing through the resistor Rs changes as the battery 1 is discharged and charged, and the polarity of the voltage generated in the resistor Rs changes. This is a circuit that always outputs a positive value. The absolute value circuit 6 outputs a voltage generated at the resistor Rs and a polarity signal indicating the polarity of the voltage. The voltage is output to a voltage / frequency (V / F) converter 7.

The V / F converter 7 is a circuit that outputs a pulse having a frequency corresponding to a voltage. For example, when the compensation capacity (500 mAh) of the battery 1 is discharged, the V / F converter 7
It outputs 0000 pulses, and outputs 18000 pulses when a capacity (50 mAh) corresponding to 10% of the compensation capacity is discharged. Similarly, when the battery 1 is charged, V /
The F converter 7 outputs 180,000 pulses when charging 500 mAh, and outputs 18,000 pulses when charging 50 mAh.

The pulse output from the V / F converter 7 is input to a counter (integrating means) 8b via a frequency divider 8a.
The polarity signal from the absolute value circuit 6 is input to the counter 8b. The frequency divider 8a is a circuit that performs control to divide the frequency of the pulse output from the V / F converter 7 into 1/180. More specifically, each time the V / F converter 7 outputs 180 pulses, one pulse is output to the counter 8b.

When the polarity signal indicates, for example, "+", the counter 8b adds the pulse counting result (U
P), and when "-" is indicated, the pulse count result is subtracted (DOWN). Each time the counter 8b counts a predetermined number of pulses, the counter 8b counts a timer (time measuring means) 9 and a FIFO (First In First Out motor current d).
ata buffers: output an interrupt signal to storage means 10. The preset number is, for example, a value of 10% of the compensation capacity when the compensation capacity of the battery 1 is 500 mAh.
A number indicating that mAh has been discharged, specifically 100 pulses.

The timer 9 is a circuit for measuring the time during which the shaving switch 3 is set to ON, that is, the driving time of the motor 2 in units of seconds. Each time an interrupt from the counter 8b is received, the timer 9 stores the time measurement result (TUS) in the FIFO 10 Is written, and a time measurement result is initialized (contents “0” is set), and a new time measurement is started. That is, the time required to discharge a capacity corresponding to 10% of the compensation capacity is measured and written to the FIFO 10.

The FIFO 10 has four timing results (TUS0 to TUS0).
Four storage areas for storing 3) are provided.
Timing result T _SUM which is the sum of timing results TUS0-3
Is output. Further, the counter 8b outputs to the CPU 11 a value obtained by truncating the least significant digit of the value stored as the counting result (the value of the upper three digits) as the counting result _CSUM . CPU1
1 monitors the on-off of the shaving switch 3 and the charging switch 4 recognizes the charge and discharge state of the battery 1 based on the state of each switch, timing result T _{SU M} and the count result C
_This is a circuit that performs an operation based on _SUM .

The CPU 11 has an average time calculating means 11
a, total time calculating means 11b, and remaining use time calculating means 11c. Average time calculation means 11a
Is the average time (T) indicating the average value of the timing results TUS0 to TUS3.
_AVE ). Specifically, the calculation of the following equation (Equation 1), average time (T _AVE ) = T _SUM / 4 · 60 [minutes] is performed.

The total time calculating means 11b calculates the average time T _AVE
Is a means for calculating the capacity at the time of completion of charging of the battery 1, that is, the total time required for discharging the compensation capacity, based on the above. Specifically, the following equation (Equation 2): Total time (T _FUL ) = 10 · T _AVE = T _SUM / 24
[Min], the following calculation is performed. In this case, the average time T _AVE, in order to show the time required to discharge 10% of the compensation capacitor, all compensation capacitance, i.e. the time required to discharge the 100% number in the average time T _{A VE} It can be calculated by multiplying by "10". Here, this numerical value is called a constant.

The remaining use time calculating means 11c refers to the count result C _SUM of the counter 8b and the total time T _FUL to refer to the battery 1
, That is, means for calculating the remaining use time in which the motor 2 can be driven based on the current capacity of the battery 1. Specifically, the following equation (Equation 3), remaining usage time (T _REM ) = T _FUL · (C _SUM / 100)
[Min], the following calculation is performed.

(C _SUM / 100) in Equation 3 is a proportional value indicating the ratio of the counting result (C _SUM ) to the compensation capacity (100%).

The remaining use time calculating means 11c outputs the count result C _SUM as the remaining capacity C _REM to the LCD drive circuit 12, and further outputs the remaining use time T _REM to the LCD drive circuit 13. The time calculated by each means is stored in a storage means such as an internal register (not shown) provided in the CPU 11 and is referred to as necessary.

The LCD driving circuits 12 and 13 include a CPU 11
The remaining capacity C _REM and remaining usage time T _REM output by
Capacity display section 14a and time display section 14 of CD panel 14
This is a circuit for performing control to selectively energize display electrodes (display segments and the like) on the LCD panel 14 in order to display on b.

The capacity display section 14a of the LCD panel 14
It comprises a plurality of display segments forming a bar graph showing the remaining capacity of the battery 1. Similarly, the time display section 14b is composed of a plurality of display segments constituting a numerical value indicating the remaining use time.

When the battery 1 is charged for the first time in the apparatus having the above configuration, the CPU 11
For example, 252 seconds are written in all the two areas. On the other hand, the counting result C _SUM indicated by the counter 8b is a counting result of the pulse output from the V / F converter 7 based on the charging current.
Indicates the content "1000".

From this state, when the shaving switch 3 is turned on and the driving of the motor 2 is started, the absolute value circuit 6 outputs a voltage corresponding to the driving current (discharge current of the battery 1) and "-".
Is output. The V / F converter 7 outputs a pulse having a frequency proportional to the voltage, and outputs the pulse to the counter 8b. When the polarity signal indicates "-", the counter 8b subtracts the content of the counter 8b according to the number of input pulses. On the other hand, the timer 9 measures the time during which the shaving switch 3 is on.

When the counter 8b counts the number of pulses corresponding to 10% of the compensation capacity, it outputs an interrupt signal to the FIFO 10 and the timer 9. FIFO1 that accepted the interrupt
At 0, the output of the timer 9 is written as TUS0. As a result, the timing result T _SUM that is the total value of the new timing results TUS0 to TUS3 is output to the CPU 11. When the timer 9 receives the interrupt signal, the timer 9 stores the time measurement result in the FIFO.
After output to 10, the timing result is initialized (the content is set to "0"), and a new timing is started.

Each time an interrupt signal is output, in other words, every time a new timing result is written to the FIFO 10, C
The average time calculation means 11a of the PU 11 calculates the average time T _AVE , and the total time calculation means 11b calculates the total time T _FUL . The calculation of the average time T _AVE and the total time T _FUL is performed every time 10% of the capacity is discharged relative to the compensation capacity.

On the other hand, while the shaving switch 3 is on, the remaining use time calculating means 11c performs an operation for calculating the remaining use time T _REM , for example, every 10 seconds. CPU
11 every time a new remaining usage time T _REM is calculated,
The LCD panel 14 is driven via the LCD drive circuits 12 and 13, and the remaining capacity C _REM is displayed on the capacity display unit 14a and the remaining use time T _REM is displayed on the time display unit 14b. The remaining capacity C _REM and the remaining use time T _REM are temporarily stored in an internal register (not shown) of the CPU 11. Then, when the remaining use time T _REM is newly calculated, it is compared with the temporarily stored remaining use time T _REM . If the value of the new remaining time T _REM is large, the new remaining usage time T _REM is discarded without performing temporary storage, that is, the display content of the time display unit 14b is not updated.

Here, the case where the battery 1 is discharged for the first time (initial discharge) and the case where the battery 1 is discharged after the second time (the next discharge) will be described with reference to FIG. FIG. 2 is an explanatory diagram relating to the display of the remaining use time of the present invention. In the figure, the vertical axis indicates the remaining use time T _REM [minutes] displayed on the time display section 14b of the LCD panel 14, and the horizontal axis indicates the discharge time of the battery 1, that is, the shaving time [seconds].

When the battery 1 is discharged for the first time, that is, immediately after charging is performed for the first time, and before the shaving switch 3 is turned on, the time measurement result of the timer 9 indicates “0”, and the time measurement results TUS0 to TUS3 of the FIFO 10 are: All show 252 seconds. That is,
Calculation result of average time calculation unit 11a (average time T _AVE )
Indicates 4.2 minutes, and the calculation result (total time T _FUL ) of the total time calculation means 11b indicates 42 minutes. At this time, LCD
The capacity display section 14a of the panel 14 indicates 100% capacity,
The time display section 14b indicates the remaining use time (MINUTES LEFT) 4
Display 2 minutes. This display indicates that the battery 1 is fully charged,
This means that the motor 2 can be driven for 42 minutes.

Thereafter, when the shaving switch 3 is turned on and the first discharge is started, every time the counter 8b counts a capacity corresponding to 10% of the compensation capacity of the battery 1, the FIFO1 is turned off.
The stored content of 0 is updated to the content that actually reflects the driving result of the motor 2, and the average time T _AVE and the total time T _FUL are updated. When the counter 8b counts the capacity corresponding to 40% of the compensation capacity, the contents of the FIFO 10 are all based on the actually measured data.

In general, there are times when the discharge current is not stable in the discharge performed after the battery 1 is completely charged for the first time. In other words, the discharge current is stabilized as the discharge proceeds. For this reason, the counter 8b has 10% to
The time measurement result written into the FIFO 10 when the capacity corresponding to 40% is counted has low reliability as a parameter for obtaining the total time T _FUL . After that, the counter 8b counts the capacity corresponding to 50% of the compensation capacity, and from the time when the timekeeping result corresponding to the capacity of 20% to 50% of the compensation capacity is written in the FIFO 10, the total time T _FUL which is almost accurate is _calculated . It has been experimentally confirmed that it can be calculated.

In the case of the figure, after counting the capacitance corresponding to 50% of the compensation capacitance, the value of the time measurement result (approximately 348 seconds) written in the FIFO 10 is stabilized, so that the remaining use time T _REM decreases almost linearly. I do.

When the remaining use time T _REM reaches 0 and charging is started, that is, when the shaving switch 3 is turned off and the charging switch 4 is turned on under the control of the charging circuit 5, the CPU 11 sets the counter 8b. The result of counting is monitored.
The absolute value circuit 6 outputs to the V / F converter 7 a voltage value corresponding to the charging current flowing in the opposite direction to the time of discharging of the battery 1, and at the same time, outputs a polarity signal indicating positive to the counter 8b. .

When receiving a positive polarity signal, the counter 8b counts the number of pulses output from the V / F converter 7. The CPU 11 has a counter 8
The count result of b is monitored, and based on the monitored result, the LCD drive circuit 12 is driven to perform display control of the capacity display unit 14a.
For example, each time the counter 8b counts the number of pulses corresponding to 20% of the compensation capacity, the CPU 11
Control is performed to light one segment of the bar graph of a.

Therefore, when the counter 8b counts the number of pulses corresponding to the compensation capacity, all the segments of the capacity display section 14a are turned on. When detecting the charging stop, the CPU 11 drives the LCD drive circuit 13 to
Immediately before the start of charging, that is, control is performed to display on the time display unit 14b the total time T _FUL which is the calculation result of the total time calculation unit 11b when the capacity display unit 14a and the time display unit 14b indicate 0. In the embodiment, “58” is displayed in the time display section 14b.
Minutes ”will be displayed.

Thereafter, using the value immediately before charging stored in the FIFO 10, that is, the time measurement result written when a stable discharge current flows from the battery 1, the average time T _AVE , The total time T _FUL and the remaining use time T _REM are calculated. That is, with respect to the discharge (next discharge) performed after the completion of the second or subsequent charging, the display content of the time display unit 14b changes almost linearly from 58 minutes to 0 minutes. This is because the absolute time required to actually discharge the battery 1 (5
8 minutes) and the time when the display of the time display section 14b changes from 58 minutes to 0 minutes.

As described above, according to the present invention, the total time T _FUL for consuming the capacity (compensation capacity) of the battery 1 when charging is completed is calculated based on the magnitude of the discharge current of the battery 1. Therefore, it is possible to display the total time T _FUL in consideration of the variation of the discharge current and the usage mode of the usage mode. Further, by accurately calculating the total time T _FUL , it is possible to make the change in the remaining use time T _{REM that} decreases with the discharge of the battery 1 substantially coincide with the absolute time. In other words, the display content of the remaining use time T _REM and the time required for actually discharging the battery 1 can be substantially matched.

The present invention is not limited to the above embodiment. In the embodiment, the writing to the FIFO 10 is performed every time 10% of the compensation capacity is discharged.
Every time, or a longer period, for example 20%
May be changed each time the battery is discharged. In the case of discharging 5%, the constant used by the remaining use time calculation unit 11c is "20", and in the case of discharging 20%, the constant is "5". In addition, the timing result written to the FIFO 10 is
The data may be temporarily stored in the CPU 11, weighted according to the value of the timing result, and then written in the FIFO 10. Specifically, if the value of the counting result is larger than the maximum value prepared in advance, this maximum value is used as the counting result in the FIFO1.
0, and when the value of the counting result is smaller than the previously prepared minimum value, the minimum value is used as the counting result.
Write to FO10. By limiting the value of the counting result in this way, it is possible to eliminate the influence of a large change in the discharge current. Further, the present invention can be applied to any device other than the shaving device, as long as it needs to calculate the dischargeable time based on the charged capacity of the battery.

[0041]

According to the apparatus for calculating the remaining use time of a battery according to the present invention, a change in the discharge current of the battery that differs for each type of use of the battery is detected, and the discharge of the compensation capacity of the battery affected by the change is detected. Since the total time, which is the time required for the use, is calculated, it is possible to accurately calculate the total time that differs for each use mode. In addition, by accurately calculating the total capacity, the remaining usage time can be easily and accurately calculated based on the integrated result of the battery discharge capacity, and the user may need to be charged. It is possible to recognize the dischargeable time until the discharge.

[Brief description of the drawings]

FIG. 1 is a block diagram of the device of the present invention.

FIG. 2 is an explanatory diagram relating to a remaining use time display according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 battery 2 motor 6 absolute value circuit 7 V / F converter 8a frequency divider 8b counter 9 timer 10 FIFO 11 CPU 11a average time calculation means 11b total time calculation means 11c remaining use time calculation means 14 LCD panel

Claims (4)

(57) [Claims] 1. A battery in which a compensation capacity regarded as a capacity at the time of completion of charging is set, a time measuring means for measuring a use time after the charging of the battery is stopped, and an accumulating means for accumulating a discharge capacity when the battery is used. Each time the integrating means completes the integration of the reference capacity, which is a part of the compensation capacity, a storing means for storing a plurality of the use times measured by the time measuring means; and a plurality of the storing means stored in the storing means. Average time calculating means for calculating an average value of the use time; and a total time calculation for calculating a total time for the compensation capacity by multiplying the average value by a constant which is a magnification for matching the reference capacity to the compensation capacity. And a remaining use time calculating means for calculating a remaining use time by multiplying a proportional value indicating a ratio between the compensation capacity and the discharge capacity by the total time. Time The device to calculate. 2. A converter for detecting an absolute value of a voltage generated in the resistor based on a resistor inserted in series with the battery and a current flowing through the resistor, and outputting a pulse having a frequency corresponding to the voltage. 2. The apparatus for calculating the remaining use time of a battery according to claim 1, further comprising a discharger, wherein the integration of the discharge capacity by the integration means is realized by counting the pulses. 3. The apparatus for calculating the remaining use time of a battery according to claim 1, further comprising a time display unit for displaying the remaining use time. 4. The apparatus according to claim 1, wherein said integrating means integrates a charge capacity of said battery when charging said battery.